In recent years, portable terminals such as portable telephone sets and PDA (Personal Digital Assistants) have been popularized remarkably. One of factors of such rapid popularization of portable terminals is considered a liquid crystal display apparatus incorporated as an output display section of the portable terminals. The reason is that the liquid crystal display apparatus has a characteristic that high power for driving the same is not required in principle and is a display device of low power consumption.
A display apparatus of a configuration wherein pixels are disposed in rows and columns (in a matrix) and are driven individually such as liquid crystal display apparatus as described above includes a vertical driving system for selecting the pixels in a unit of a row and a horizontal driving system for writing information into each of the pixels of the row selected by the vertical driving system. Various timing pulses for driving control of the driving systems are used by them.
The timing pulses are generated at suitable timings based on a horizontal synchronizing signal HD, a vertical synchronizing signal VD and a master clock signal MCK using a timing signal producing counter circuit for exclusive use or the like. The timing pulse generation circuit for generating the timing pulses is conventionally formed on a single crystal silicon substrate which is separate from a substrate on which a display area section is formed.
Where, in a display apparatus represented by a liquid crystal display apparatus, a timing generation circuit for generating various timing signals to be used for display driving is formed on a substrate separate from a substrate on which a display area section is formed as described above, the number of parts for forming the set increases and they must be produced through separate processes. Therefore, there is a problem that miniaturization and reduction of the cost of the set are obstructed.
Therefore, it is an object of the present invention to provide a timing generation circuit for a display apparatus which can contribute to miniaturization and reduction of the cost of a set and a display apparatus in which the timing generation circuit is incorporated.